How to bake uv map texture to vertex color (selected to active)?
I don't know if this is exactly what you want, but maybe these steps can help you (do a backup before doing anything!):


Do UV mapping and apply texture to your object.
Apply Dynamic Paint to your object.
We will transfer that Texture color information into Vertex Colors. And this is how you do it. Under Dynamic Paint attribute:





Once you done that, you hit Apply under Modifier to complete the bake of Vertex Color into the Vertex.
Now you will have an object with Vertex Color that originated from UV Texture. 


I got it from this link: link

Go ahead to the section "Bake texture as vertex color". It's the same as i posted plus some other maybe useful information.